Multi-layered high-density recording medium and optical power adjusting method therefor

ABSTRACT

The present invention relates to a multi-layered high-density recording medium and an optical power adjusting method therefor. A multi-layered high-density recording medium of the present invention includes optical power related information for all layers, and a optical power adjusting method of the present invention reads first optical power related information for all layers from a multi-layered optical disk placed in a disk player, stores the read information in another storage device, and immediately makes a current optical power optimal to a moved layer without accessing the placed multi-layered optical disk by referring to the stored optical power related information when moving to another layer during record or reproduction.

1. TECHNICAL FIELD

The present invention relates to a multi-layered high-density recordingmedium and an optical power adjusting method therefor.

2. BACKGROUND ART

Recently, the standardization for Blu-ray Rewritable (referred to asBD-RE hereinafter), which is a new high-density rewritable optical disk,capable of recording high-quality video and audio data for a long time,is in rapid progress. BD-RE related products will be available on themarket when the standardization is completed.

The data recording layer of a single-layered BD-RE disk is located at adistance of 0.1 mm from the disk surface in the direction normal to anobjective lens 11 contained in an optical pickup, as illustrated in FIG.1.

For recording/reproducing data on/from the recording layer of the BD-RE,the laser power of a laser diode (LD) 13 contained in the optical pickupis adjusted according to the operation mode, which will be described indetail below.

FIG. 2 shows a table of disk information recorded in the lead-in area ofa conventional single-layered BD-RE. The lead-in area comprises apre-recorded area and a rewritable area and the pre-recorded areaincludes a PIC (Permanent Information & Control) data zone.

As illustrated in FIG. 2, information such as the disk information ID,the disk structure, and a maximum DC read power and a maximumhigh-frequency modulated read power for adjusting read power is recordedin the PIC data zone.

Also, write power settings at a normal recording velocity, write powersettings at a maximum recording velocity, and write power settings at aminimum recording velocity for adjusting write power are recorded in thePIC data zone.

An optical disk apparatus in which the BD-RE having the informationshown in FIG. 2 is placed adjusts the amount of the current that flowsthrough the LD contained in the optical pickup optimal to the presentoperation mode by referring to the disk information stored in the PICdata zone before beginning reproducing data recorded on the recordinglayer of the BD-RE or recording data on the recording layer of theED-RE.

On the other hand, dual-layered BD-RE disks having a storage capacitytwice as much as that of a single-layered BD-RE disk have been proposed.A dual-layered BD-RE has two recording layers, Layer 1 and Layer 2,located at a prescribed distance (d2) away from each other, asillustrated in FIG. 3.

The optical power of the LD 13 needs to be adjusted appropriately forrecording data on a layer or reproducing data from a layer in the sameway as the case for a single-layered disk. If optical power relatedinformation only for either of the layers is recorded or an identicaloptical power is employed for both layers, the recording/reproducingperformance is likely to be deteriorated on one of the two layers. Forexample, suppose that an optical read power set appropriately for Layer1 is used to read data recorded on Layer 2. A portion of the laser beamreflected by Layer 2 is reflected again by Layer 1 located below. Also,a portion of the laser beam created by the LD 13 is reflected by Layer 1before reaching Layer 2, which results in an optical loss. For thesereasons, the data recorded on Layer 2 may not be read successfully,though data reproducing on Layer 1 is successful.

As a result, it is required to maintain optical power relatedinformation for each of the recording layers separately. Optical powerrelated data for Layer 1 is recorded in the lead-in area of Layer 1 andoptical power related data for Layer 2 is recorded in the lead-out areaof Layer 2. When jumping from Layer 1 to Layer 2 in the middle of areproducing/reading operation on Layer 1, the reproducing/readingoperation on Layer 2 cannot start immediately after the jump until theoptical power related information recorded on the lead-out area of Layer2 is accessed.

3. DISCLOSURE OF THE INVENTION

In an effort to solve the foregoing needs, it is the object of thepresent invention to provide a multi-layered high-density recordingmedium and an optical power adjusting method therefor. In the opticalpower adjusting method with the high-density recording medium, opticalpower can be adjusted optimal to each of the recording layersimmediately after a layer jump operation is performed, thereby allowingfast start of a read/write operation after the layer jump.

A high-density optical disk in accordance with the invention containsoptical power adjustment-related information for each of a plurality ofrecording layers.

An optical power adjustment method in accordance with the inventioncomprises the steps of reading optical power adjustment information forall of a plurality of recording layers from a multi-layered optical diskplaced in an apparatus and storing the optical power adjustmentinformation; searching the stored information to find the optical poweradjustment information for a recording layer that is the target of arequested reproducing/recording operation; and setting an optical powerappropriate for the recording layer by referring to the found opticalpower adjustment information.

Another optical power adjustment method in accordance with the inventioncomprises the steps of: reading optical power adjustment information forall of a plurality of recording layers from a multi-layered optical diskplaced in an apparatus and storing the optical power adjustmentinformation in a storage means; and, in case of jumping to anotherrecording layer during a recording or reproducing session on a recordinglayer, setting an optical power appropriate for the recording layer thatis the target of the jump operation by referring to the optical poweradjustment information stored in the storage means without accessing theoptical disk and continuing the recording or reproducing operation onthe target recording layer.

The high-density multi-layered optical disk and optical power adjustmentmethod in accordance with the invention provides fast optical poweradjustment capability and thereby prevents a momentary pause ofrecording/reproducing operation even in case of layer jumps.

4. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the structure of a single-layered disk and an opticalpickup for accessing the disk;

FIG. 2 illustrates a table of disk information recorded in the lead-inarea of a single-layered BD-RE;

FIG. 3 illustrates the structure of a dual-layered disk and an opticalpickup for accessing the disk;

FIG. 4 illustrates PIC data zones assigned to lead-in and lead-out areasof a high-density dual-layered optical disk in accordance with theinvention;

FIG. 5 illustrates a table of disk information stored in the PIC datazone assigned in a dual-layered optical disk in accordance with theinvention;

FIG. 6 illustrates an optical disk apparatus in which the presentinvention may be advantageously embodied;

FIG. 7 illustrates a flow diagram of an optical power adjusting methodin accordance with one embodiment of the invention;

FIG. 8 illustrates a flow diagram of an optical power adjusting methodin accordance with another embodiment of the invention; and

FIGS. 9 a and 9 b illustrate the structure of ADIP words in whichoptical power adjustment-related information for a plurality ofrecording layers is stored.

5. BEST MODE FOR CARRYING OUT THE INVENTION

In order that the invention may be fully understood, preferredembodiments thereof will now be described with reference to theaccompanying drawings.

FIG. 4 illustrates the structure of a dual-layered BD-RE disk inaccordance with the invention, wherein a lead-in area and a lead-outarea of the disk exist on Layer 1 and Layer 2 respectively and eachlayer has an outer zone in the outer-diameter of the disk.

The lead-in area of Layer 1 and lead-out area of Layer 2 containseparate PIC data zones that contain the same optical power related datafor adjusting read/write optical power for both recording layers.

In other words, the PIC data zones recorded in the lead-in area of Layer1 and lead-out area of Layer 2 contain the same disk information. Asillustrated in FIG. 5, the disk information includes disk information IDand disk structure information. The disk structure information is anidentification number indicative of a dual-layered optical disk. Theidentification number may indicate the number of recording layers. Forexample, ‘0000 0011’ indicates a three-layer disk, ‘0000 0010’ indicatesa dual-layered disk, and ‘0000 0001’ indicates a single-layered disk.

The disk information further includes a maximum DC read power for Layer1 and a maximum DC read power for Layer 2, a maximum high-frequencymodulated read power for Layer 1, and a maximum high-frequency modulatedread power for Layer 2, all information being for adjusting read powersfor Layer 1 and Layer 2.

The disk information further includes write power settings at a normalrecording velocity for Layer 1, write power settings at a normalrecording velocity for Layer 2, write power settings at a maximumrecording velocity for Layer 1, write power settings at a maximumrecording velocity for Layer 2, write power settings at a minimumrecording velocity for Layer 1, and write power settings at a minimumrecording velocity for Layer 2, all information being for adjustingwrite powers for Layer 1 and Layer 2.

In case of a three-layer optical disk, the disk information includesoptical power related information corresponding to each of threerecording layers. Likewise, in case of an N-layer optical disk, the diskinformation includes optical power related information corresponding toeach of N recording layers.

FIG. 6 illustrates a block diagram of an optical disk apparatus such asa video disk recorder (VDR) embodying the invention. The optical diskapparatus comprises an optical pickup 50 for reading recorded signalsfrom a dual-layered BD-RE disk 200 or for recording external input dataon the BD-RE disk 200, a VDR system 51 for processing the signalsreceived from the optical pickup 50 or for converting an input datastream into a data stream formatted for recording, and an encoder 52 forencoding an external analog input signal and outputting the encodedsignal to the VDR system 51.

FIG. 7 illustrates a flow diagram of recording/reproducing data on/fromthe dual-layered BD-RE disk 200 in the optical disk apparatus shown inFIG. 6.

Once the dual-layered BD-RE disk 200 is inserted, the VDR system 51starts a disk loading operation (S10).

Then the optical disk apparatus accesses the lead-in area located onLayer 1 of the dual-layered BD-RE 200 by moving the optical pickup 50(S11) and performs a pre-read/pre-write operation of reading the diskinformation and defect address management information (called ‘DMA’)recorded in the lead-in area and storing the read information in amemory (not illustrated in FIG. 6) contained in the optical diskapparatus (S12). Optical power related information is read once by thepre-read/pre-write operation.

If a request to record data on BD-RE 200 or to reproduce data from BD-RE200 is received (S13), the VDR system 51 examines for which layer therequest is issued.

If the request is associated with Layer 1 (S14), the VDR system 51searches the disk information stored in the memory for the optical powerrelated data for Layer 1 (S15).

Then the optical disk apparatus adjusts the read/write optical power ofthe LD contained in the optical pickup 50 according to the read opticalpower related data for Layer 1 (S16).

After the optical power adjustment operation finishes, the optical diskapparatus begins the requested read/write operation on Layer 1(S17).

If the received request to read data or to record data is associatedwith Layer 2, the VDR system 51 searches the disk information stored inthe memory for the optical power related data for Layer 2 included inthe disk information (S18), adjusts the read/write optical power of theLD according to the read optical power related data for Layer 2 (S19),and performs the requested read/write operation (S20).

If a request for a layer jump, for example, a jump from Layer 1 to Layer2, is received while a read/write operation is being performed (S21),the VDR system 51 adjusts the optical power of the LD suitably for Layer2 by consulting the optical power adjustment-related information forLayer 2 stored in the memory (S22) before starting a read/writeoperation on Layer 2 (S23).

Consequently, in the case of jump operations, a data read/writeoperation can resume immediately after the jump operation without anadditional latency.

FIG. 8 illustrates a flow diagram of an optical power adjustment methodin accordance with another embodiment of the invention, wherein opticalpower adjustment-related information for Layer 1 is recorded only in thelead-in area of Layer 1 and optical power adjustment-related informationfor Layer 2 is recorded only in the lead-out area of Layer 2.

Once the dual-layered BD-RE disk 200 is inserted, the VDR system 51starts a disk loading operation (S30).

Then the optical disk apparatus accesses the lead-in area located onLayer 1 and the lead-out area located on Layer 2 successively by movingthe optical pickup 50 (S31) and reads the disk information and defectaddress management information to store the read information in a memory(not illustrated in FIG. 6) contained in the optical disk apparatus(S32). Disk information recorded on every recording layers is read oncein this manner before the requested read/write operation.

If a request to record data on BD-RE 200 or to reproduce data from BD-RE200 is received (S33), the VDR system 51 examines for which layer therequest is issued.

If the request is associated with Layer 1 (S34), the VDR system 51searches the disk information stored in the memory for the optical powerrelated data for Layer 1 (S35).

Then the optical disk apparatus adjusts the read/write optical power ofthe LD contained in the optical pickup 50 according to the read opticalpower related data for Layer 1 (S36).

After the optical power adjustment operation finishes, the optical diskapparatus begins the requested read/write operation on Layer 1(S37).

If the received request to read data or to record data is associatedwith Layer 2, the VDR system 51 searches the disk information stored inthe memory for the optical power related data for Layer 2 included inthe disk information (S38), adjusts the read/write optical power of theLD according to the read optical power related data for Layer 2 (S39),and performs the requested read/write operation (S40).

If a request for a layer jump, for example, a jump from Layer 1 to Layer2, is received while a read/write operation is being performed (S41),the VDR system 51 adjusts the optical power of the LD suitably for Layer2 by consulting the optical power adjustment-related information forLayer 2 stored in the memory (S42) before starting a read/writeoperation on Layer 2 (S43).

Consequently, though optical power adjustment-related information foreach recording layer is stored only on the corresponding layer, a dataread/write operation can resume immediately after a jump operationwithout an additional latency.

Instead of recording the optical power adjustment-related information inthe PIC data zone assigned to the lead-in and lead-out areas asdescribed above, it is possible to record the optical poweradjustment-related information in the ADIP (Address In Pregroove)encoded in wobble tracks. The ADIP formation format is as follows.

56 nominal wobble lengths (NWLs) constitute an ADIP unit. An ADIP unithas 9 different types as illustrated in FIG. 9 a. 83 ADIP units in turnconstitute an ADIP word. FIG. 9 b illustrates the format of an ADIPword. As shown in FIG. 9 b, an ADIP word may contain 60-bit data(nibbles c0-c14), which are recorded by encoding for error correctionand hence contain 36 information bits.

24 bits of the 36 information bits are used as an ADIP address and theremaining 12 bits are used as auxiliary information. Since an ADIP wordcan store 12-bit auxiliary information, N ADIP words are grouped tosecure a space enough for storing optical power adjustment-relatedinformation and the optical power adjustment-related information for allthe layers is stored there. The information -is stored repeatedly ingroups of N ADIP words.

Although certain specific embodiments of the present invention have beendisclosed, it is noted that the present invention may be embodied inother forms without departing from the spirit or essentialcharacteristics thereof. The present embodiments are therefore to beconsidered in all respects as illustrative and not restrictive, thescope of the invention being indicated by the appended claims, and allchanges that come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

1. A high-density optical disk, comprising a plurality of recordinglayers and containing optical power adjustment-related information foreach of the plurality of recording layers.
 2. The high-density opticaldisk set forth in claim 1, wherein said optical power adjustment-relatedinformation for each of the plurality of recording layers is recordedequally on each of the plurality of recording layers.
 3. Thehigh-density optical disk set forth in claim 1, wherein said opticalpower adjustment-related information is recorded in disk informationzone contained in the permanent information control (PIC) data zoneassigned to said optical disk.
 4. The high-density optical disk setforth in claim 3, wherein disk information stored in said diskinformation zone includes read optical power related data for all of theplurality of recording layers, write optical power related data for allof the plurality of recording layers, and disk structure information forall of the plurality of recording layers.
 5. The high-density opticaldisk set forth in claim 4, wherein said read optical power related dataincludes maximum DC read power data and maximum high-frequency modulatedread power data.
 6. The high-density optical disk set forth in claim 4,wherein said write optical power related data includes write power dataat a normal recording velocity, write power data at a maximum recordingvelocity, and write power data at a minimum recording velocity.
 7. Thehigh-density optical disk set forth in claim 4, wherein said diskstructure information is information indicative of the number ofrecording layers formed in said optical disk.
 8. The high-densityoptical disk set forth in claim 1, wherein said optical poweradjustment-related information for each of the plurality of recordinglayers is recorded in said recording layers in a distributed manner andoptical power adjustment-related information recorded in each of theplurality of recording layers includes information only for thecorresponding recording layer.
 9. The high-density optical disk setforth in claim 1, wherein said optical power adjustment-relatedinformation for each of the plurality of recording layers is encoded inwobble tracks.
 10. The high-density optical disk set forth in claim 1,wherein said optical power adjustment-related information for each ofthe plurality of recording layers is recorded in the lead-in area of arecording layer and in the lead-out area of another recording layer. 11.An optical power adjustment method, comprising the steps of: (a) readingoptical power adjustment-related information for respective recordinglayers from a multi-layered optical disk and storing the read opticalpower adjustment-related information; (b) searching the storedinformation to find the optical power adjustment-related information fora recording layer that is the target of a requestedreproducing/recording operation; and (c) setting an optical powerappropriate for the recording layer based on the found optical poweradjustment-related information.
 12. The optical power adjustment methodset forth in claim 11, wherein said step (a) reads the optical poweradjustment-related information for the respective recording layers froma specific area assigned to an arbitrary recording layer.
 13. Theoptical power adjustment method set forth in claim 11, wherein said step(a) reads the optical power adjustment-related information for all ofthe plurality of recording layers by searching all of the plurality ofrecording layers sequentially.
 14. The optical power adjustment methodset forth in claim 11, further comprising the step of: searching thestored information to find the optical power adjustment-relatedinformation for the recording layer that is the target of a jumpoperation in case of jumping to another recording layer during arecording or reproducing session on a recording layer and setting anoptical power appropriate for the target recording layer by referring tothe found optical power adjustment-related information.
 15. An opticalpower adjustment method, comprising the steps of: reading optical poweradjustment-related information for all of the plurality of recordinglayers from a multi-layered optical disk and storing the optical poweradjustment-related information in a storage means; and setting anoptical power appropriate for the recording layer that is the target ofthe jump operation by referring to the optical power adjustment-relatedinformation stored in said storage means without accessing said opticaldisk, in case of jumping to another recording layer during a recordingor reproducing session on a recording layer and continuing the recordingor reproducing operation on the target recording layer.
 16. An opticalpower adjustment method, comprising the steps of: obtaining opticalpower information to read or write data from or to an optical recordingmedium, said optical recording medium including at least two recordinglayers, and the optical power information for the respective recordinglayers being recorded on a specific area of the recording medium; andcontrolling a reading or writing operation based on the optical powerinformation corresponding to the recording layer.
 17. The method ofclaim 16, wherein said optical power information includes referencepower values for a plurality of recording velocities corresponding tothe recording layer, and wherein the controlling step controls a writingoperation based on a reference power value for a specific recordingvelocity corresponding to the recording layer.
 18. The method of claim16, wherein said optical power information includes reference read powervalues corresponding to the recording layer, and wherein the controllingstep controls a reading operation based on each of the reference readpower values corresponding to the recording layer.
 19. An opticalrecording medium, comprising: at least two recording layers; and anoptical power information area which includes respective reference powervalues for a plurality of recording velocities corresponding to therecording layer.
 20. The optical recording medium of claim 19, whereinthe optical power information area further includes a reference readpower value corresponding to the recording layer.
 21. The opticalrecording medium of claim 19, wherein the optical power information areais located in an inner part of specific recording layer.
 22. The opticalrecording medium of claim 19, wherein the optical power information areais formed in ADIP (Address In Pre-groove) modulated in a wobbled track.23. An optical recording medium, comprising: at least two recordinglayers; and an optical power information area which includes respectivereference power values for a plurality of recording velocities andreference read power values corresponding to the recording layer.